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        <h2>
          <span class="refentrytitle">reson</span>
        </h2>
        <p>reson — 
      A second-order resonant filter.
          </p>
      </div>
      <div class="refsect1">
        <a id="idp142141632"></a>
        <h2>Description</h2>
        <p>
      A second-order resonant filter.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp142142848"></a>
        <h2>Syntax</h2>
        <pre class="synopsis">ares <span class="command"><strong>reson</strong></span> asig, xcf, xbw [, iscl] [, iskip]</pre>
      </div>
      <div class="refsect1">
        <a id="idp142215184"></a>
        <h2>Initialization</h2>
        <p>
      <span class="emphasis"><em>iscl</em></span> (optional, default=0) -- coded scaling factor for resonators. A value of 1 signifies a peak response factor of 1, i.e. all frequencies other than kcf are attenuated in accordance with the (normalized) response curve. A value of 2 raises the response factor so that its overall RMS value equals 1. (This intended equalization of input and output power assumes all frequencies are physically present; hence it is most applicable to white noise.) A zero value signifies no scaling of the signal, leaving that to some later adjustment (see <a class="link" href="balance.html" title="balance"><em class="citetitle">balance</em></a>). The default value is 0.
    </p>
        <p>
      <span class="emphasis"><em>iskip</em></span> (optional, default=0) -- initial disposition of internal data space. Since filtering incorporates a feedback loop of previous output, the initial status of the storage space used is significant. A zero value will clear the space; a non-zero value will allow previous information to remain. The default value is 0.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp142219872"></a>
        <h2>Performance</h2>
        <p>
      <span class="emphasis"><em>ares</em></span> -- the output signal at audio rate.
    </p>
        <p>
      <span class="emphasis"><em>asig</em></span> -- the input signal at audio rate.
    </p>
        <p>
      <span class="emphasis"><em>xcf</em></span> -- the center frequency of the filter, or frequency position of the peak response.
    </p>
        <p>
      <span class="emphasis"><em>xbw</em></span> -- bandwidth of the filter (the Hz difference between the upper and lower half-power points).
    </p>
        <p>
      <span class="emphasis"><em>reson</em></span> is a second-order filter in which <span class="emphasis"><em>kcf</em></span> controls the center frequency, or frequency position of the peak response, and <span class="emphasis"><em>kbw</em></span> controls its bandwidth (the frequency difference between the upper and lower half-power points).
    </p>
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      <div class="refsect1">
        <a id="idp142226544"></a>
        <h2>Examples</h2>
        <p>
      Here is an example of the reson opcode. It uses the file <a class="ulink" href="examples/reson.csd" target="_top"><em class="citetitle">reson.csd</em></a>.

      </p>
        <div class="example">
          <a id="idp142228320"></a>
          <p class="title">
            <strong>Example 752. Example of the reson opcode.</strong>
          </p>
          <div class="example-contents">
            <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
-odac   <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc    ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o reson.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="ohdr">sr</span> <span class="op">=</span> 44100 
<span class="ohdr">ksmps</span> <span class="op">=</span> 32 
<span class="ohdr">0dbfs</span>  <span class="op">=</span> 1 
<span class="ohdr">nchnls</span> <span class="op">=</span> 2

<span class="oblock">instr</span> 1

asaw <span class="opc">vco2</span> .2, 220	<span class="comment">;sawtooth</span>
kcf  <span class="opc">line</span> 220, p3, 1760	<span class="comment">;vary cut-off frequency from 220 to 1280 Hz</span>
kbw  <span class="op">=</span> p4		<span class="comment">;vary bandwidth of filter too		</span>
ares <span class="opc">reson</span> asaw, kcf, kbw
asig <span class="opc">balance</span> ares, asaw
     <span class="opc">outs</span> asig, asig

<span class="oblock">endin</span>
<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="stamnt">i</span> 1 0 4 10	<span class="comment">;bandwidth of filter = 10 Hz</span>
<span class="stamnt">i</span> 1 + 4 50	<span class="comment">;50 Hz and</span>
<span class="stamnt">i</span> 1 + 4 200	<span class="comment">;200 Hz</span>
<span class="stamnt">e</span>
<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
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        <p><br class="example-break" />
    </p>
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      <div class="refsect1">
        <a id="idp142232640"></a>
        <h2>See Also</h2>
        <p>
      <a class="link" href="areson.html" title="areson"><em class="citetitle">areson</em></a>,
      <a class="link" href="aresonk.html" title="aresonk"><em class="citetitle">aresonk</em></a>,
      <a class="link" href="atone.html" title="atone"><em class="citetitle">atone</em></a>,
      <a class="link" href="atonek.html" title="atonek"><em class="citetitle">atonek</em></a>,
      <a class="link" href="port.html" title="port"><em class="citetitle">port</em></a>,
      <a class="link" href="portk.html" title="portk"><em class="citetitle">portk</em></a>,
      <a class="link" href="resonk.html" title="resonk"><em class="citetitle">resonk</em></a>,
      <a class="link" href="tone.html" title="tone"><em class="citetitle">tone</em></a>,
      <a class="link" href="tonek.html" title="tonek"><em class="citetitle">tonek</em></a>
    </p>
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      <div class="refsect1">
        <a id="idp142242432"></a>
        <h2>Credits</h2>
        <p>Audio rate parameters introduced in version 6.02</p>
        <p>November 2013.</p>
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